To provide a control device of a robot having an arm which causes the arm to be stopped more easily than conventionally by generating a load of appropriate magnitude to an operator during lead-through. The present invention relates to a control device of a robot having an arm, the control device including: a motor that generates torque in each axis of the robot; a torque generation control unit that controls the motor so as to generate a canceling torque which cancels friction of each axis of the robot when controlling the robot by external force tracking; and a torque changing unit that changes the canceling torque to a reference value or less.
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1. A control device of a robot having an arm, the control device comprising: a motor that generates torque in each axis of the robot; a torque generation control unit that controls the motor so as to generate a canceling torque which cancels friction of each axis of the robot when controlling the robot by external force tracking; and a torque changing unit that changes the canceling torque to a reference value or less.
This invention relates to a control device for a robot arm designed to improve external force tracking by compensating for friction. The device addresses the challenge of accurately controlling a robot arm when subjected to external forces, where friction in the joints can introduce errors and instability. The control device includes a motor that generates torque in each axis of the robot arm. A torque generation control unit regulates the motor to produce a canceling torque that counteracts friction in each axis during external force tracking operations. This ensures smoother and more precise movement by minimizing the disruptive effects of friction. Additionally, a torque changing unit adjusts the canceling torque to a predefined reference value or lower, preventing excessive torque that could lead to instability or damage. The system dynamically compensates for friction while maintaining safe and controlled operation, enhancing the robot's ability to respond accurately to external forces. This approach is particularly useful in applications requiring high precision, such as collaborative robotics or tasks involving direct human interaction.
2. The control device according to claim 1 , wherein the torque changing unit changes the canceling torque based on a speed feedback value from the motor, or an estimated value of a force applied by a user to the arm.
A control device for a motor-driven system, such as a power-assisted steering or robotic arm, addresses the challenge of precisely controlling motor torque to compensate for external forces or user inputs. The device includes a torque changing unit that dynamically adjusts a canceling torque applied by the motor to counteract disturbances or user-applied forces. This unit modifies the canceling torque based on either a speed feedback value from the motor or an estimated value of the force applied by a user to the arm. The speed feedback value provides real-time motor performance data, allowing the system to adjust torque in response to detected speed variations, which may indicate external disturbances. Alternatively, the estimated force value, derived from sensors or computational models, enables torque adjustments based on the user's interaction with the arm. By dynamically adapting the canceling torque, the system ensures smooth and accurate motor operation, improving stability and responsiveness in applications requiring precise force control. The invention enhances performance in systems where external forces or user inputs must be compensated for without manual intervention.
3. The control device according to claim 2 , wherein, in a case in which the speed feedback value or the estimated value is a first threshold value or less, the torque changing unit changes the canceling torque to a value between zero or more and a second threshold value or less, and in a case in which the speed feedback value or the estimated value is a third threshold value which is greater than the first threshold value or more, the torque changing unit changes the canceling torque to a value between zero or more and a fourth threshold value which is greater than the second threshold value or less.
A control device for a motor or actuator system adjusts a canceling torque applied to counteract an external disturbance force, such as friction or vibration. The device includes a speed feedback or estimated speed value to determine the system's operating conditions. The control device dynamically modifies the canceling torque based on the speed feedback or estimated value. When the speed is at or below a first threshold, the canceling torque is adjusted to a value between zero and a second threshold. This ensures minimal interference with normal operation while still mitigating disturbances. When the speed exceeds a third threshold, which is higher than the first, the canceling torque is increased to a range between zero and a fourth threshold, which is higher than the second. This allows for stronger disturbance suppression at higher speeds. The thresholds are set to balance performance and stability, ensuring the system responds appropriately to varying operating conditions. The torque adjustment logic prevents excessive torque application, maintaining smooth and efficient operation. This approach is useful in applications requiring precise motion control, such as robotics, automotive systems, or industrial automation.
4. The control device according to claim 2 , wherein, in a case in which a distance between a boundary of an operable area of the arm and a center point of a tip end portion of the arm is a fifth threshold value or less, the torque changing unit changes the canceling torque so that the distance and a gain used for changing the canceling torque have a positive correlation, and sets the gain to zero when the distance is zero.
This invention relates to a control device for an arm, particularly for adjusting torque to improve operational safety and precision. The arm operates within a defined area, and the control device monitors the distance between the arm's tip and the boundary of this operable area. When this distance falls below a predefined threshold, the control device modifies the canceling torque applied to the arm. The adjustment ensures that the torque change is proportional to the distance, with a positive correlation between the distance and the gain used for torque modification. If the arm's tip reaches the boundary (distance zero), the gain is set to zero, effectively stopping further torque adjustments. This mechanism helps prevent the arm from exceeding its operable area while maintaining smooth and controlled movements. The control device may also include a torque command generator to produce initial torque commands and a torque changing unit to adjust these commands based on the arm's position relative to the boundary. The system ensures safe and precise operation by dynamically adapting torque control as the arm approaches the boundary of its operable space.
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August 28, 2020
April 19, 2022
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